Epoxy molding compound for chip encapsulation based on spherical silicon oxide

Abstract

This invention discloses an epoxy molding compound for chip packaging based on spherical silicon oxide, belonging to the field of epoxy molding compound technology. The epoxy molding compound of this invention, by weight, comprises 200-300 parts spherical silicon oxide, 30-60 parts high-temperature resistant epoxy resin, 30-80 parts curing agent, 4-12 parts diluent, 0.6-1.5 parts curing accelerator, and 4-9 parts coupling agent. The high-temperature resistant epoxy resin has an epoxy functionality of 8, providing a large number of epoxy groups, which readily forms a three-dimensional structure with high cross-linking density. Combined with the naphthalene ring backbone and imide ring structure, it exhibits excellent thermal stability and mechanical properties, and its coefficient of thermal expansion is significantly lower than that of o-cresyl formaldehyde epoxy resin. It also has higher flexural strength, making it more suitable for high-performance epoxy resin-based electronic packaging materials.

Description

Technical Field

[0001] This invention relates to the field of epoxy molding compound technology, specifically to epoxy molding compounds for chip packaging based on spherical silicon oxide. Background Technology

[0002] In the integrated circuit industry, packaging is a critical manufacturing process. High-performance packaging materials and precise, orderly packaging processes maximize the performance of integrated circuits. Electronic packaging can be simply defined as a component that protects the integrated circuit from environmental interference and extends its lifespan. Specifically, electronic packaging materials refer to the outer sealing layer of electronic components. This sealing layer plays a crucial role in supporting electronic components and interconnects, isolating them from the external environment, and conducting and dissipating heat. Based on these functions, excellent electronic packaging materials must possess certain mechanical properties, good sealing and moisture-proofing properties, excellent thermal conductivity and heat dissipation, good thermal expansion coefficient matching, and insulation and flame retardancy. Among these, polymer-based electronic packaging materials have advantages such as low density, low manufacturing cost, and fast molding speed. Epoxy molding compounds are an important representative of polymer-based electronic packaging materials, mainly composed of epoxy resin, thermally conductive fillers, and functional additives. They have good electrical insulation and excellent corrosion resistance, and are widely used in the field of electronic packaging materials. However, standard epoxy molding compounds typically operate at temperatures not exceeding 150°C, making them unsuitable for the packaging requirements of power electronic devices. Traditional high-temperature resistant polymer resins, including polyimide (PI), bismaleimide (BMI), cyanate ester resin (CE), benzoxazine resin (PBZ), cyano resin, benzocyclobutene (BCB), and silicone resin, still lag significantly behind EMC standards and are difficult to match with currently used EMC packaging processes. Furthermore, epoxy resins exhibit poor toughness after curing and are prone to brittle fracture under stress. Additionally, epoxy molding compounds often use electronic-grade epoxy resins as the matrix, requiring a total chlorine content of less than 0.1% to prevent the release of organic chlorine compounds during use, which could corrode the leads of integrated circuits and cause failure. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides an epoxy molding compound for chip packaging based on spherical silicon oxide, which solves the problems of insufficient high temperature resistance and flexural strength, and high chlorine content of epoxy resin in the prior art.

[0004] The technical solution for achieving the objective of this invention is as follows:

[0005] The epoxy molding compound for chip encapsulation based on spherical silica comprises, by weight, 200-300 parts spherical silica, 30-60 parts high-temperature resistant epoxy resin, 30-80 parts curing agent, 4-12 parts diluent, 0.6-1.5 parts curing accelerator, and 4-9 parts coupling agent. The high-temperature resistant epoxy resin has the following molecular structure:

[0006] .

[0007] In one specific embodiment, the U content of the spherical silica is <5 ppb.

[0008] In one specific embodiment, the method for preparing the high-temperature resistant epoxy resin includes the following steps:

[0009] S1. 2,6-Dibromonaphthalene-1,4,5,8-tetracarboxylic anhydride was reacted with mono-Boc-1,6-hexanediamine under anhydrous and oxygen-free conditions to obtain intermediate A;

[0010] S2. Use trifluoroacetic acid to remove the Boc protection of intermediate A to obtain intermediate B;

[0011] S3. Under anaerobic and light-protected conditions, intermediate B was reacted with arachidonic acid under N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine activated catalysis to obtain intermediate C;

[0012] S4. Under oxygen-free and light-protected conditions, peracetic acid is used to oxidize the alkenyl group of intermediate C to obtain a high-temperature resistant epoxy resin.

[0013] In one specific embodiment, the reaction temperature in step S1 is 60~80℃, the reaction time is 2~6 hours, the molar ratio of 2,6-dibromonaphthalene-1,4,5,8-tetracarboxylic anhydride to mono-Boc-1,6-hexanediamine is 1:(2.01~2.1), and the solvent is N,N-dimethylacetamide.

[0014] In one specific embodiment, the reaction temperature in step S2 is 0~5℃, the reaction time is 10~30min, the concentration of trifluoroacetic acid in the system is 15~20v / v, and the solvent is anhydrous dichloromethane.

[0015] In one specific embodiment, the reaction temperature in step S3 is room temperature, the reaction time is 2-6 hours, the molar ratio of intermediate B to arachidonic acid is 1:(2.01-2.1), the solvent is anhydrous dichloromethane, the amount of N,N'-dicyclohexylcarbodiimide added is 2-2.5 times the molar amount of intermediate B, and the amount of 4-dimethylaminopyridine added is 10-30 mol of the molar amount of intermediate B.

[0016] In a specific embodiment, the reaction temperature in step S4 is a gradient temperature increase reaction, specifically -10℃ for 1~2 hours of stirring reaction, 0℃ for 1~2 hours of stirring reaction, and room temperature for 1~2 hours of stirring reaction, with the molar ratio of intermediate C to peracetic acid being 1:(8~15); the solvent is anhydrous dichloromethane.

[0017] In one specific embodiment, the diluent is ethylene glycol diglycidyl ether, the curing agent is methyltetrahydrophthalic anhydride or linear phenolic resin, the curing accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diaza-bicyclo(5,4,0)-7-undecene, imidazole, and triphenylphosphine, and the coupling agent is a mercaptosilane coupling agent.

[0018] In one specific embodiment, the mercaptosilane coupling agent is selected from one or more of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldiethoxysilane.

[0019] Another object of the present invention is to protect the preparation method of the epoxy molding compound for chip packaging based on spherical silicon oxide, comprising the following steps:

[0020] (1) Surface treatment of spheroidized silicon oxide using a coupling agent;

[0021] (2) Mix the high-temperature resistant epoxy resin, curing agent, diluent and curing accelerator thoroughly, add the surface-treated spherical silica and mix evenly and degas under vacuum to obtain epoxy molding compound.

[0022] Beneficial effects

[0023] This invention provides an epoxy molding compound for chip packaging based on spherical silica. The resulting high-temperature resistant epoxy resin has an epoxy functionality of 8, providing a large number of epoxy groups. It exhibits advantages such as low chlorine content, low epoxy equivalent, and low softening point, making it easy to process and readily forming a high-crosslink density three-dimensional structure after curing. The surface of the spherical silica is treated with a silane coupling agent. The active thiol groups on the silane coupling agent can further react with the bromine on the naphthalene ring backbone of the high-temperature resistant epoxy resin at the curing temperature, enhancing the bonding force between the filler and the epoxy resin substrate and reducing its coefficient of linear expansion. The naphthalene ring skeleton and imide ring structure contained in epoxy resin exhibit excellent thermal stability and mechanical properties, and have a low coefficient of thermal expansion, making them suitable for high-performance epoxy resin-based electronic packaging materials. The resulting epoxy molding compound has significantly better linear expansion coefficient, flexural strength, and heat distortion temperature performance than bisphenol A type epoxy resin and o-cresol aldehyde type epoxy resin, and its performance is comparable to that of dicyclopentadiene phenol type phenolic epoxy resin, with an advantage in organochlorine content. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the synthesis route for high-temperature resistant epoxy resin.

[0025] Figure 2 The 1H NMR spectrum of intermediate B;

[0026] Figure 3 The 1H NMR spectrum of high-temperature resistant epoxy resin. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise specified, the experimental methods used in the embodiments are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0029] The raw materials used in the examples and comparative examples are described below:

[0030] High-temperature resistant epoxy resin: self-made, preparation method is as follows:

[0031] S1. Add 0.04 mol of 2,6-dibromonaphthalene-1,4,5,8-tetracarboxylic anhydride and 600 ml of anhydrous N,N-dimethylacetamide to a reaction vessel, heat until dissolved, purge with nitrogen for 30 min, dissolve 0.084 mol of mono-Boc-1,6-hexanediamine in 20 ml of anhydrous N,N-dimethylacetamide, and slowly add it to the reaction system. Heat to 70 °C and stir for 4 hours. After the reaction is complete, cool to room temperature, pour in 10 times the volume of cold sodium chloride solution to precipitate the solid, filter, wash twice with water, and dry under vacuum at 50 °C to obtain intermediate A, with a yield of 82.6%.

[0032] S2. Dissolve 0.03 mol of intermediate A in 100 mL of anhydrous dichloromethane. Place the reaction system in an ice bath, add a mixed solution of 50 mL trifluoroacetic acid and 100 mL dichloromethane, stir for 15 min to remove BOC protection, and after the reaction, slowly quench with saturated NaHCO3 solution until the pH of the aqueous phase is ≥7; separate the layers and collect the lower organic phase; back-extract the aqueous phase once with 50 mL DCM, combine the organic phases, wash successively with 50 mL saturated NaHCO3 and 50 mL saturated NaCl solutions, then dry with anhydrous sodium sulfate or magnesium sulfate for 30 min, filter, rotary evaporate, remove the desiccant, concentrate under reduced pressure below 30 °C, and finally dry in a vacuum drying oven at 30 °C to obtain intermediate B, with a yield of 81.2%;

[0033] S3. Under a nitrogen atmosphere and in the dark, the reaction vessel was placed in an ice bath. 0.02 mol of intermediate B, 0.042 mol of arachidonic acid, 0.044 mol of N,N'-dicyclohexylcarbodiimide (DCC), 0.004 mol of 4-dimethylaminopyridine, and 100 mL of anhydrous dichloromethane were added sequentially. After thorough mixing, the ice bath was removed, and the mixture was stirred at room temperature for 4 hours. The resulting white precipitate was removed by filtration and washed once each with saturated sodium bicarbonate solution, dilute hydrochloric acid (0.5 mol / L), and saturated sodium chloride solution. The precipitate was dried over anhydrous magnesium sulfate and purified by column chromatography (mobile phase: ethyl acetate: n-hexane = 1:3) to obtain intermediate C, with a yield of 78.9%.

[0034] S3. Under a nitrogen atmosphere and in the dark, add 0.01 mol of intermediate C and 100 ml of anhydrous dichloromethane to a reaction vessel. Dissolve 16.5 ml of 39% peracetic acid in 30 ml of anhydrous dichloromethane. Transfer the reaction system to a -10°C freezer. Add the peracetic acid solution dropwise. After mixing, continue stirring at -10°C for 1 h, then transfer to 0°C and stir for 2 h. Finally, stir at room temperature for 2 h to obtain epoxy resin. Wash once each with cold saturated NaHCO3 and Na2SO3 solutions, dry with anhydrous magnesium sulfate, and purify by column chromatography (fluidity: ethyl acetate / n-hexane = 1:1). The yield is 64.5%. The reaction process is as follows: Figure 1 As shown, the 1H NMR spectroscopy of intermediate B and the high-temperature resistant epoxy resin confirmed their structural formulas as follows: Figure 2 and Figure 3 As shown.

[0035] Bisphenol A type epoxy resin: R-140, E51 type, industrial grade, Mitsui Group, Japan;

[0036] o-Cresol-formaldehyde epoxy resin: SQCN700-1, industrial grade, Shandong Shengquan New Material Co., Ltd.;

[0037] Dicyclopentadiene phenolic epoxy resin, SQDN-302, industrial grade, Shandong Shengquan New Material Co., Ltd.

[0038] Spherical silica: Sourced from Guangzhou Yushun New Material Technology Co., Ltd., prepared using acidic silica sol, sodium silicate solution, and dilute sulfuric acid (all industrial grade) as raw materials in a turbulent circulating reactor. The resulting spherical silica has a purity greater than 99.98%, a sphericity greater than 95%, radioactive element U < 0.3 ppb, and alpha particle flux < 0.02 cph / cm². 2 .

[0039] Coupling agent: 3-mercaptopropyltrimethoxysilane, industrial grade, Shin-Etsu Chemical Co., Ltd., Japan;

[0040] Curing accelerator: 2,4,6-tris(dimethylaminomethyl)phenol, industrial grade, Wuhan Baiyite Chemical Co., Ltd.

[0041] Curing agent: Methyltetrahydrophthalic anhydride, 80%, Shanghai Maclean Biochemical Technology Co., Ltd.;

[0042] Diluent: Ethylene glycol diglycidyl ether, JF-810, Ningxia Jufeng New Material Technology Co., Ltd., epoxy equivalent 115-122 g / mol;

[0043] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0044] Examples and Comparative Examples

[0045] An epoxy molding compound for chip packaging based on spherical silicon oxide is prepared by the following method:

[0046] (1) Mix deionized water and methanol in a certain volume ratio, add mercaptosilane coupling agent first, hydrolyze for 15-20 min, then add spherical silicon oxide, stir magnetically at room temperature for 12 h, wash the surface-treated spherical silicon oxide three times with deionized water and ethanol respectively, filter and put it into a vacuum drying oven, dry at 105℃ for 2 h to obtain surface-treated spherical silicon oxide.

[0047] (2) Thoroughly mix the high-temperature resistant epoxy resin, diluent, curing agent, and curing accelerator, add the surface-treated spherical silica, mix evenly, and degas under vacuum. Pour the degassed slurry into a mold and place it in a forced-air drying oven. Cur it at 130°C for 2 hours. After demolding, obtain the epoxy molding compound cured sample.

[0048] Table 1 Raw materials and proportions (molar parts) of epoxy molding compound

[0049]

[0050] The epoxy resins and epoxy molding compounds prepared in the examples and comparative examples were subjected to the following performance tests, and the results are shown in Tables 2 and 3, respectively.

[0051] 1. Epoxy equivalent: Referring to standard GB / T 1677-2023 "Determination of epoxy value of plasticizers", the epoxy equivalent of the epoxy resins in the examples and comparative examples was determined by hydrochloric acid-acetone back titration method.

[0052] 2. Softening point: The softening point of the epoxy resins in the examples and comparative examples was determined according to the standard GB / T 12007.6-1989 "Determination of Softening Point of Epoxy Resins - Ring and Ball Method".

[0053] 3. Organic chlorine content: The organic chlorine content of the epoxy resins in the examples and comparative examples was determined in accordance with the standard GB / T 4618.2-2008 "Determination of chlorine content in epoxy resins for plastics - Part 2: Saponifiable chlorine".

[0054] 4. Inorganic chlorine content: The inorganic chlorine content of the epoxy resins in the examples and comparative examples was determined according to the standard GB / T 4618.1-2008 "Determination of chlorine content in epoxy resins for plastics - Part 1: Inorganic chlorine"; the detection limit was 1 ppm.

[0055] 5. Coefficient of linear expansion: The coefficient of linear expansion of the epoxy molding compounds in the examples and comparative examples was determined with reference to the standard GB / T 1036-2008 "Determination of the coefficient of linear expansion of plastics at -30℃~30℃ - Quartz dilatometer method".

[0056] 6. Bending strength: The bending strength of the epoxy molding compounds in the examples and comparative examples was determined in accordance with the standard GB / T 2570-1995 "Test method for bending properties of resin castings".

[0057] 7. Heat distortion temperature: The heat distortion temperature of the epoxy molding compounds in the examples and comparative examples was determined with reference to standard GB / T 1634.2-2019 "Determination of load distortion temperature of plastics - Part 2: Plastics and hard rubber".

[0058] Table 2. Epoxy resin performance test results of the examples and comparative examples.

[0059]

[0060] Chlorine atoms in epoxy resin molecules exist in three different forms: hydrolyzable chlorine, non-hydrolyzable chlorine, and inorganic chlorine, which are generally collectively referred to as total chlorine. Since both hydrolyzable and non-hydrolyzable chlorine exist in the epoxy resin molecule through chemical bonds, they are generally collectively referred to as organic chlorine. Organic chlorine present in epoxy resin often precipitates during the use of epoxy molding compounds, subsequently corroding the leads of integrated circuits and causing integrated circuit failure. As can be seen from the test results in Table 2, the high-temperature resistant epoxy resin prepared in this invention, due to the absence of epichlorohydrin in the preparation process, has extremely low organic and inorganic chlorine content, and a low epoxy equivalent (i.e., a high epoxy value), which is beneficial for forming a high-temperature resistant, high-crosslink density three-dimensional structure.

[0061] Table 3. Performance test results of epoxy molding compounds in the examples and comparative examples.

[0062]

[0063] As can be seen from the test results in Table 3, the epoxy molding compound prepared by this invention has significantly better linear expansion coefficient, flexural strength and heat distortion temperature performance than bisphenol A type epoxy resin and o-cresol type epoxy resin, and its performance is comparable to that of dicyclopentadiene phenol type phenolic epoxy resin. It also has the advantages of low epoxy equivalent and low chlorine content.

[0064] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An epoxy molding compound for chip packaging based on spherical silicon oxide, characterized in that, By weight, the product comprises 200-300 parts spherical silica, 30-60 parts high-temperature resistant epoxy resin, 30-80 parts curing agent, 4-12 parts diluent, 0.6-1.5 parts curing accelerator, and 4-9 parts coupling agent. The high-temperature resistant epoxy resin has the following molecular structure: 。 2. The epoxy molding compound as described in claim 1, characterized in that, The radioactive element U content of the spherical silicon dioxide is <5 ppb.

3. The epoxy molding compound as described in claim 1, characterized in that, The preparation method of the high-temperature resistant epoxy resin includes the following steps: S1. 2,6-Dibromonaphthalene-1,4,5,8-tetracarboxylic anhydride was reacted with mono-Boc-1,6-hexanediamine under anhydrous and oxygen-free conditions to obtain intermediate A; S2. Use trifluoroacetic acid to remove the Boc protection of intermediate A to obtain intermediate B; S3. Under anaerobic and light-protected conditions, intermediate B was reacted with arachidonic acid under N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine activated catalysis to obtain intermediate C; S4. Under oxygen-free and light-protected conditions, peracetic acid is used to oxidize the alkenyl group of intermediate C to obtain a high-temperature resistant epoxy resin.

4. The epoxy molding compound as described in claim 3, characterized in that, The reaction temperature in step S1 is 60~80℃, the reaction time is 2~6 hours, the molar ratio of 2,6-dibromonaphthalene-1,4,5,8-tetracarboxylic anhydride to mono-Boc-1,6-hexanediamine is 1:(2.01~2.1); the solvent is N,N-dimethylacetamide.

5. The epoxy molding compound as described in claim 3, characterized in that, The reaction temperature in step S2 is 0~5℃, the reaction time is 10~30min, the concentration of trifluoroacetic acid in the system is 15~20v / v; the solvent is anhydrous dichloromethane.

6. The epoxy molding compound as described in claim 3, characterized in that, The reaction temperature in step S3 is room temperature, the reaction time is 2-6 hours, the molar ratio of intermediate B to arachidonic acid is 1:(2.01-2.1), the solvent is anhydrous dichloromethane, the amount of N,N'-dicyclohexylcarbodiimide added is 2-2.5 times the molar amount of intermediate B, and the amount of 4-dimethylaminopyridine added is 10-30 mol of the molar amount of intermediate B.

7. The epoxy molding compound as described in claim 3, characterized in that, The reaction temperature in step S4 is a gradient temperature increase reaction, specifically -10℃ for 1~2 hours of stirring, 0℃ for 1~2 hours of stirring, and room temperature for 1~2 hours of stirring. The molar ratio of intermediate C to peracetic acid is 1:(8~15). The solvent is anhydrous dichloromethane.

8. The epoxy molding compound as described in claim 1, characterized in that, The diluent is ethylene glycol diglycidyl ether, the curing agent is methyltetrahydrophthalic anhydride or linear phenolic resin, the curing accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diaza-bicyclo(5,4,0)-7-undecene, imidazole, and triphenylphosphine, and the coupling agent is a mercaptosilane coupling agent.

9. The epoxy molding compound as described in claim 8, characterized in that, The mercaptosilane coupling agent is selected from one or more of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldiethoxysilane.

10. The method for preparing epoxy molding compound for chip packaging based on spherical silicon oxide as described in any one of claims 1 to 9, characterized in that, Includes the following steps: (1) Surface treatment of spheroidized silicon oxide using a coupling agent; (2) Mix the high-temperature resistant epoxy resin, curing agent, diluent and curing accelerator thoroughly, add the surface-treated spherical silica and mix evenly and degas under vacuum to obtain epoxy molding compound.

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